ALLAH SEES, KNOWS, AND HEARS EVERYTHING

All liars have two things in common: They do not know Allah and they deny that He sees and hears everything. While they may deceive those around them, conceal certain things or gain a personal advantage, they cannot deceive Allah, Who sees, hears, and knows everything, and Who is the only Reckoner of what is true and correct. Allah tells us about this in the following verse:

They try to conceal themselves from people, but they cannot conceal themselves from Allah. (Surat an-Nisa', 4:108)

However, liars cannot achieve their aims, because their intelligence and faith are inadequate, and because they believe that they have protected themselves when they deceive other people. In fact, such people can neither harm nor benefit themselves.
Believers who are aware of this truth should not forget that every word, every thought, and every concealed thing is known to Allah, and that they have to behave at every moment with the awareness of this fact. Certain verses, some of which are mentioned below, state this truth:

Do you not see that Allah knows what is in the heavens and on Earth? Three men cannot confer together secretly without Him being the fourth of them, or five without Him being the sixth of them, or fewer than that or more without Him being with them wherever they are. Then He will inform them on the Day of Rising of what they did. Allah has knowledge of all things. (Surat al-Mujadala, 58:7)

He knows the eyes' deceit and what people's breasts conceal. (Surah Ghafir, 40:19)

Do they not know that Allah knows what they keep secret and what they make public? (Surat al-Baqara, 2:77)

Allah-Him from Whom nothing is hidden, either on Earth or in Heaven. (Surah Al 'Imran, 3:5)

He is Allah in the heavens and in the earth. He knows what you keep secret and what you make public, and He knows what you earn. (Surat al-An`am, 6:3)